Means for controlling electric motors.



I Patented Ian; I, l90l. J. GREEN 6. G. C. THOM.

MEANS FOR CONTROLLING ELECTRIC MOTORS.

(Applicstioi: filed June 15, 1900.;

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UNKTED STATES PATENT Orricn.

JOHN GREEN AND GEORGE C. THOM, OF JOHNSTOWN, PENNSYLVANIA.

MEANS FOR CONTROLLING ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 665,324, dated January 1, 1901.

Application filed June 15, 1900- Serial No. 20,441. (No model.)

To all whom it may concern:

Be it known that we, JOHN GREEN and GEORGE O. THOM, of Job nstown, in the county of Cambria and State of Pennsylvania, have invented new and useful Improvements in Means for Controlling Electric Motors, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

Ourinvention has relation to means for controlling the operation of the motors of electric cranes of that type which are provided with main and auxiliary hoists, driven each by its own motor. Heretofore four separate motor-controllers have generally been employed on cranes of this type, one for controlling the longitudinal traverse of the crane, another for controlling the transverse movement of the hoist-carriage, and one each for the main and auxiliary hoist, these four controllers being arranged across one side of the operators cage. The operation of the end controllers requires the operator to move so 1, far to one side of the cage as to make it difficult for him to properly observe the Work going on below at the opposite side of the cage and time the movements of the crane and hoists with respect thereto.

The objects of our present invention are to simplify the controlling mechanism and also to obviate the difficulty above referred to. These objects We accomplish by connecting the circuits of both the main and auxiliary hoist-motors to a single controller and interposing in such circuits a switch, the proper operation of which in connection with the controller will enable the latter to control either motor at will. This switch we place at a point in the cage where it can be reached by the operator without moving substantially from his position and without interference with his observations of the work going on below.

Our invention also consists in the novel construction and combination of parts, all as hereinafter described, and pointed out in the appended claims, reference being had to the accompanying drawings, which form part of this specification.

In the drawings, Figures 1 and 2 are diagrams showing the circuit arrangements, and Fig. 3 is an elevation of an electric crane.

The letter A designates the main arm or bridge of the crane, which is mounted to move longitudinally on the track-rails B. Cis the hoist-carriage, mounted on the bridge B. D is the main hoist, and E the auxiliary hoist. M is the motor for the main hoist. The motor for the auxiliary hoist is at the opposite side of the crane and is not shown in Fig. 3 but appears at M in the diagram, Fig. 1. These parts are all constructed and arranged in the usual manner and do not require detailed description or illustration.

G is the controller, which by our invention is made to control both motors M and M As herein shown, it consists of fixed contact fingers or brushes b, b b b b and and a rotary member carrying the contacts 0 c c c c 0 the relative disposition of which will best appear from Figs. 1 and 2, Fig. 2 showing said member turned through an arc of one hundred and eighty degrees from the position which it occupies in Fig. 1.

R indicates artificial resistance, and B Oindicate the coil of the usual brake-magnets.

S is a switch consisting of nine fixed contacts, numbered from 1 to 9, inclusive, on the drawings and arranged in three parallel rows, and a movable member composed of an operating-handle and triple blades, the latter being respectively pivoted to the contacts 4, 5, and 6 of the middle row of contacts and adapted to be moved to engage the corresponding contacts of either the upper or lower row. Contact-finger b is connected to the contact 4, finger b is connected to contact 5, and finger b is connected to contact 6. Fingers b and b are connected to each other through the resistance R. Finger b is connect-ed to the supply-circuit at T.

Contacts 1 and 3 of the switch S are connected to opposite terminals of the field-coils F of motor M, and contact 2 is connected to ground through the armature A of said motor. Contacts 7 and 9 are similarly connected to the field-coils F of motor M and contact 8 is connected to ground through the armature A of motor M With the controller and switch in the position shown in Fig. 1, the circuit, beginning at T, is through finger I), contact finger 19 contacts 4 and 1, to and through the fieldcoils of M, to contacts 3 and 6, to finger b contact 0 finger b resistance R, finger b, contact 0, finger b to contacts 5 and 2, to and through armature A to ground. Aportion of the current is shunted around the motor through the brake-magnet coils B C.

When the controller is moved to the position shown in Fig. 2, the circuit is the same as above described, except that the current through the fields F F is reversed. The switch S is omitted from this figure, which is illustrative merely of the particular type of controller described. When the switch S is moved over to a position where its blades engage the contacts 7, 8, and 9, motor M is entirely disconnected from the controller and motor M is connected therewith in precisely the same manner as was motor M in the first position of said switch. This will readily apscribed, as various types and constructions may be employed, nor do we wish to he limited in other respects to non-essential details of construction and arrangement.

Having thus described our invention, what we claim, and desire to secure by Letters Patent, is-

1. The combination with two electric mo tors having independent field and armature circuit connections, and designed to operate different mechanisms, of a controller, and .a switch for connecting the circuits of either motor to said controller at will. i

2. The combination with two electric motors having independent field and armature circuits, of a controller, and a switch having one set of contacts connected to the field and armature coils of one motor, a second set similarl y connected'to the coils of the other motor, and a third set connected to the source of ourrent-supply through the said controller, said switch also having a movable member provided with contact devices which are electrically connected to the contacts of the lastnanied set, and are arranged to be engaged with the contacts of either the first or second set.

3. In an electric crane, a main hoist, an auxiliary hoist, an electric motor for each of said hoists, a single controller for both motors, and a switch for operatively connecting said controller with either of said motors and at the same time disconnect it from the other motor.

In testimony whereof we have affixed our signatures in presence'of two witnesses.

JOHN GREEN. GEO. O. THOM.

Witnesses:

GEO. H. PARMELEE, H. W. S ITH. 

